Space Commodity—Field Museum First to Receive Portion of ‘Pristine’ Michigan Meteorite for Study

Field Museum Scientist and Robert A Pritzker Associate Curator of Meteoritics and Polar Studies Philipp Heck holds the piece of meteorite recovered after the fall in Michigan on January 2018. Photo by Marielle Shaw. It came from outer space... and streaked across the sky outside of Detroit on January 16. Now, thanks to a meteorite hunter named Robert Ward's partnership with the Field Museum who recovered and preserved a piece of this stellar find, a space rock that broke off an asteroid and fell to earth has been placed in the capable hands of scientists at the Field Museum (after a short journey from Michigan courtesy FedEx). The Field Museum is the first institution to receive a piece of the meteorite from the January fall, and we were there as Philipp Heck, the Robert A. Pritzker Associate Curator of Meteoritics and Polar Studies and his staff were investigating the sample for the first time. The Field Museum has the second largest collection of meteorites in the country, with 14,000 of the space rocks carefully preserved just beyond the walls of Stanley Field Hall, but this particular meteorite is something truly out of this world.  This 22 g sample of the meteorite is in plastic to preserve its rare "pristine" nature- any humidity in the room could compromise the sample. Photo by Marielle Shaw. There are 60,000 named meteorites known to science, and the 24-gram sample the Field Museum received is just one in that myriad. It's a common type of meteorite, too, known as a chondrite—and its composition, or what we know of it as of press date, is fairly common for meteorites, too. So why all the hullabaloo around this tiny rock from space?   Collections Manager for Meteorites and Physical Geology Jim Holstein, showing us some of the 14,000 meteorites the Field Museum has in its collection. Photo by Marielle Shaw. It has a lot to do with how scientists study meteorites, and how they obtain them from hunters like Robert Ward. Often, once a meteorite falls to the earth, it takes weeks or even months to reach a scientist. Oftentimes the meteorite has already seen water, which can dissolve minerals and compromise the sample, and colonies of bacteria can settle in, further damaging it.  This wasn't the case, though, with the January 16 Hamburg meteorite. It was found just two days after it fell to eart, and happened to land on a frozen lake. These two factors—the speed at which it was recovered and the area where it was found, make this meteorite priority for the Field—and a particularly exciting discovery.   One of the 14,000 meteorites in the Field Museum's collecitons. Photo by Marielle Shaw. "We're really excited about this January 16th fall," says Philipp. We had a bright fireball over the Midwest and just two days later the pieces were found and later made their way into the Field Museum. Two weeks ago this was still in space." Heck continues, "This is really important for us because it's a fresh fall—it was found only a few days after the fall. It's better preserved than any of the other meteorites we have in our collection. We have 14,000 meteorites at the Field Museum and this is the best preserved one, not only because it fell very recently, but also because it was found very quickly after the fall. It didn't see water, it was found on a frozen lake. You can argue ice also is water, but since it wasn't liquid it didn't do anything to compromise the sample."  Philipp Heck in the lab where active study is being done on the Michigan Meteorite for the first time. Photo by Marielle Shaw. This is also why the meteorite stayed within the confines of a plastic bag, a vacuum or dessicator, save for the 2 g sample currently in the lab's electron microscope. Since it is so pristine, scientists including Heck and the Field Museum's Collections Manager for Meteorites and Physical Geology Jim Holstein, are hoping they can learn new things from it—perhaps find new minerals, maybe even recover stardust, though Heck thinks that might be a long shot. What they've already learned or are suspecting is that the meteorite likely came from the asteroid belt between Mars and Jupiter, and like most chondrites dates all the way back to the early solar system. They found silicate, phosphates and are looking for salt or halite. These minerals can help them do important dating work that will further our understanding of our solar system.   Jennika Greer, a PhD student helping to study the meteorite in the lab. Photo by Marielle Shaw After spending the first few days looking at the sample in the microscope, it's likely the Field Museum's scientists will run the rock through a mass spectrometer to get further information to help them date it. Because the meteorite is so pristine and new though, there's potential for scientists at the Field to find things in this meteorite that they've never seen before in any other, and understand meteorites and the known universe better than before because of it.   Photo by Marielle Shaw One of the most exciting things about the Field Museum has always been the untold treasures that you don't see in the exhibit halls. 99 percent of the priceless artifacts and specimens that the museum has collected since the World’s Columbian Exposition in 1893 are out of view, but it's also in the active science and research happening every day just out of sight that constantly progresses our understanding of the world around us and beyond. It's these things that make the Field Museum a true Chicago treasure. 
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Marielle Bokor